(a) Field of the Invention
The present invention relates to a thinner composition for removing photosensitive resin (resist) film, used in TFT-LCD (thin film transistor liquid crystal display) and semiconductor device manufacturing processes, and more particularly to a thinner composition capable of effectively removing unnecessary film constituents formed at edges of the resist film coated on the substrate or formed at the back of the substrate during manufacturing processes of TFT-LCD devices and semiconductor devices.
(b) Description of the Related Art
In pattern formation of a fine circuit like a TFT-LCD circuit or a semiconductor integrated circuit, a resist composition is uniformly coated or applied on an insulation film or a conductive metal film formed on the substrate. Then, the coated resist composition is exposed and developed in the presence of a mask having a certain pattern to acquire the pattern. The metal film or the insulation film is etched using the patterned resist film as mask, and the remaining resist film is removed to form a fine circuit. When manufacturing TFT-LCDs or semiconductor devices with this lithography method, the resist film should be formed on a substrate such as glass or silicon wafer, and the substrate should be rinsed with a thinner prior to exposure and developing of the resist film, in order to remove unnecessary resist constituents on the edge of the formed resist film and unnecessary resist film formed at the back of the substrate.
For thinners to rinse and remove the resist film on the substrate, water, inorganic and organic alkaline thinners, and organic amine thinners like monoethanolamine are known. With the inorganic alkaline thinners, inorganic materials remain after removing unnecessary films, so that they may contaminate the processing equipment, and the removing efficiency is poor. Therefore, organic alkalis and organic amines are used as main components of the thinner, and inorganic alkalis as minor components. The organic alkalis and organic amines leave few unwanted materials after they are evaporated, so that they do not corrode the equipment. Additionally, since they have good solubility to the resist, they have superior resist-removing efficiency.
Other thinner compositions comprise inorganic alkalis like potassium hydroxide, sodium hydroxide, sodium phosphate, sodium silicate, sodium carbonate, or sodium hydrogen carbonate; organic alkalis like tetramethylammonium hydroxide; and organic solvents like dipropyleneglycol monomethylether, propyleneglycol monomethylether, propyleneglycol monomethyl ether acetate, or n-butyl acetate. However, these organic solvents do not offer sufficient resist-removing efficiency, and in particular, an increase in the content of inorganic alkalis causes problems with equipment corrosion after evaporation.
Therefore, development of a new thinner composition having superior resist-removing efficiency and that is capable of preventing equipment corrosion is needed.